Battery goes dead on my home Generac generator

Generac, Guardian, Honeywell, Siemens, Centurion, Watchdog, Bryant, & Carrier Air Cooled Home Standby generator troubleshooting and repair questions
Post Reply
Gosh
New Member
New Member
Posts: 5
Joined: Tue Sep 10, 2019 5:51 pm

Tue Sep 10, 2019 6:53 pm

I have a 12 kw GT990 Generac Centurian Generator as a backup for my home. Serial Number 5339329. I purchased and had it installed from Lowes in 2012. The only issue I have ever had with it was the control panel LED screen went blank, or maybe more descriptively burned out, about a year into my owning the unit. However, the unit still worked normally, I just could not change anything because I could not read the monitor. I do a oil change maintenance on it each year. I noticed it had not been doing it's weekly 15 minute test about 6 months ago. I discovered the battery had gone dead. This was the second battery in the lifetime of the generator and had been in the generator for at least 2 years with everything running fine. I purchased a new battery and the unit fired up fine and I thought I had fixed the problem. It took me about 3 weeks to notice it was not working again and discovered the new battery was dead. I tried to charge the new battery but it would not hold the charge. Fortunately the store honored the battery warranty and I have a new battery. But, I am afraid to install it only to have this one discharged as well. It appears to me I have a problem somewhere in the generator that is causing my battery to discharge but I am not really sure where to begin looking. i have a good Sperry voltmeter, but, I am not real knowledgeable in its use or the language of Ohms, Amps, volts, watts, etc. Please help.
Chris
Site Admin
Site Admin
Posts: 1359
Joined: Sat Aug 04, 2018 8:46 pm
Location: Clawson, MI
Contact:

Tue Sep 10, 2019 7:17 pm

This is most certainly a bad battery charger.

You'll find a charger in the transfer switch which you can see here: https://shop.gentekpower.com/products/g ... connectors

It was fairly common for the older versions that came with them to fail...
Generac tech for over 12 years. I'm here to help!
"The only source of knowledge is experience" -Albert Einstein
Looking for Generac parts? Gentek Power offers the full line of Generac replacement parts! Shop Gentek Power Generac Parts
A list of my favorite Generator & Electrical Tools! https://www.amazon.com/shop/gentek_power
Gosh
New Member
New Member
Posts: 5
Joined: Tue Sep 10, 2019 5:51 pm

Fri Sep 13, 2019 9:26 pm

Where can I find the transfer switch?
Chris
Site Admin
Site Admin
Posts: 1359
Joined: Sat Aug 04, 2018 8:46 pm
Location: Clawson, MI
Contact:

Fri Sep 13, 2019 10:20 pm

The transfer switch is the main box that transfers power from utility to the generator. It may be time to call your local Generac dealer in for some help.
Generac tech for over 12 years. I'm here to help!
"The only source of knowledge is experience" -Albert Einstein
Looking for Generac parts? Gentek Power offers the full line of Generac replacement parts! Shop Gentek Power Generac Parts
A list of my favorite Generator & Electrical Tools! https://www.amazon.com/shop/gentek_power
Gosh
New Member
New Member
Posts: 5
Joined: Tue Sep 10, 2019 5:51 pm

Sun Sep 15, 2019 9:09 am

Found it. Thanks.
Chris
Site Admin
Site Admin
Posts: 1359
Joined: Sat Aug 04, 2018 8:46 pm
Location: Clawson, MI
Contact:

Sun Sep 15, 2019 10:23 am

I'm glad to hear it! Just make sure when changing the charger out that ALL power is off to the transfer switch. That means the main house power and the generator are both off and confirmed dead with a meter. The transfer switch has live 240V inside.
Generac tech for over 12 years. I'm here to help!
"The only source of knowledge is experience" -Albert Einstein
Looking for Generac parts? Gentek Power offers the full line of Generac replacement parts! Shop Gentek Power Generac Parts
A list of my favorite Generator & Electrical Tools! https://www.amazon.com/shop/gentek_power
Gosh
New Member
New Member
Posts: 5
Joined: Tue Sep 10, 2019 5:51 pm

Sun Sep 29, 2019 2:33 pm

I ordered the replacement charger off the link you sent to me. The charger came but there are no instructions included. The new one has a black wire with two leads, both black, coming out of one end, and a wire coming out of the other end with two leads, one red and one black. The old charger, which I have not removed yet, also has a wire coming out of both ends with two leads but both wires are only black. How do I know which way to route the red and black wire? Also, you indicated to turn off the house power. Is it not enough to just flip the breaker to the transfer switch panel from the main panel?
Chris
Site Admin
Site Admin
Posts: 1359
Joined: Sat Aug 04, 2018 8:46 pm
Location: Clawson, MI
Contact:

Sun Sep 29, 2019 10:55 pm

The old charger will have 1 wire marked "0". That is DC ground (-).

On the new charger, the pair of wires with the red wire is DC output. Those will be the 15B and 0 wires. Match the black wire of the pair to the 0 wire and the red positive to the 15B terminal.

The other 2 black wires are the T1 and neutral. They do not care which is which.

Flipping the breaker off will shut the power off, but the generator MUST be disabled so that it doesn't start.
Generac tech for over 12 years. I'm here to help!
"The only source of knowledge is experience" -Albert Einstein
Looking for Generac parts? Gentek Power offers the full line of Generac replacement parts! Shop Gentek Power Generac Parts
A list of my favorite Generator & Electrical Tools! https://www.amazon.com/shop/gentek_power
Gosh
New Member
New Member
Posts: 5
Joined: Tue Sep 10, 2019 5:51 pm

Fri Oct 04, 2019 6:20 pm

OK Chris, AWESOME!!! directions and I have gotten the new battery charger installed and the generator back up and running smoothly. While I don't want to get a big head because I am feeling pretty good about myself for solving this issue, I am wondering about the display and the problem I have with not being able to read it. If you remember from my first post, the display burned out on me a year or so into owning the generator (now 8 years old). Should I worry about the display? It would be nice to know and/or change the time the thing comes on to run it's test trial each week. What kind of cost and complications would I be running into with replacing the display unit?
Chris
Site Admin
Site Admin
Posts: 1359
Joined: Sat Aug 04, 2018 8:46 pm
Location: Clawson, MI
Contact:

Sat Oct 05, 2019 7:45 pm

I have never tried to replace the LCD module, however I do think it's soldered onto the PCB. If you're not real handy with a precision soldering iron and some solder, that may be a tricky repair...

The controllers normally get replaced as a whole but are pricey...

https://shop.gentekpower.com/products/g ... trol-panel
Generac tech for over 12 years. I'm here to help!
"The only source of knowledge is experience" -Albert Einstein
Looking for Generac parts? Gentek Power offers the full line of Generac replacement parts! Shop Gentek Power Generac Parts
A list of my favorite Generator & Electrical Tools! https://www.amazon.com/shop/gentek_power
Post Reply